From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE9331FB3; Tue, 27 May 2025 17:45:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748367949; cv=none; b=jrZ+jagQUHJe9Mvdm1vgGjMMBLQmPUdnRa1c1Sw8O5B2exRGWmXSfl3A37AH3nxNNcCJkcRWgSlnQFaBluMNdiie0VGrB/nslUCX5QkC7FabFYIZdmbVroo9p2dta5dAXvF2obIcWwO7uA0QYIw5u9Oea5seR+NBIQGXXxQjbys= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748367949; c=relaxed/simple; bh=gdZKinPIfxyxn7b8t0VBt6WKEZE0fRa6xFuz9xKNXq0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JJEx3rPlHau+2THtT9gov4O4D1255rN0hEf+VmGt1zkc5wKem20N3CC9hyTHL50xMs0QASTlxogP9nHYJ/gPaucFFqK91JbIvklg2NpeCiZEmjfFB95XdOyhZ8aABF+dgAaYFySasZYH2Mw6KaMm2DfsWVCiUI1dJZc2qOtZQMY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1vnGAevC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1vnGAevC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64109C4CEE9; Tue, 27 May 2025 17:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748367948; bh=gdZKinPIfxyxn7b8t0VBt6WKEZE0fRa6xFuz9xKNXq0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1vnGAevCk+RX54Bnd8EdrGDk07T5QuvzGbbdVCcM9KvYhG6PXi1vtT04ipU+5ReQr cORHUVd2fbmMTg/KMdnm1SKnKeAVGGwaJih+1Jyo08mgMAuuGzPaCae11KZo+mtKSn 7Qj0w8qwAOpUnwhx4SqyTMGRzQKregKpp+FUCQxY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mina Almasry , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.14 551/783] net: page_pool: avoid false positive warning if NAPI was never added Date: Tue, 27 May 2025 18:25:48 +0200 Message-ID: <20250527162535.589476526@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250527162513.035720581@linuxfoundation.org> References: <20250527162513.035720581@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jakub Kicinski [ Upstream commit c1e00bc4be06cacee6307cedb9b55bbaddb5044d ] We expect NAPI to be in disabled state when page pool is torn down. But it is also legal if the NAPI is completely uninitialized. Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250206225638.1387810-4-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/dev.h | 12 ++++++++++++ net/core/page_pool.c | 7 ++----- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/net/core/dev.h b/net/core/dev.h index a5b166bbd169a..caa13e431a6bc 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -299,6 +299,18 @@ void xdp_do_check_flushed(struct napi_struct *napi); static inline void xdp_do_check_flushed(struct napi_struct *napi) { } #endif +/* Best effort check that NAPI is not idle (can't be scheduled to run) */ +static inline void napi_assert_will_not_race(const struct napi_struct *napi) +{ + /* uninitialized instance, can't race */ + if (!napi->poll_list.next) + return; + + /* SCHED bit is set on disabled instances */ + WARN_ON(!test_bit(NAPI_STATE_SCHED, &napi->state)); + WARN_ON(READ_ONCE(napi->list_owner) != -1); +} + void kick_defer_list_purge(struct softnet_data *sd, unsigned int cpu); #define XMIT_RECURSION_LIMIT 8 diff --git a/net/core/page_pool.c b/net/core/page_pool.c index ede82c610936e..cca51aa2e876f 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -25,6 +25,7 @@ #include +#include "dev.h" #include "mp_dmabuf_devmem.h" #include "netmem_priv.h" #include "page_pool_priv.h" @@ -1146,11 +1147,7 @@ void page_pool_disable_direct_recycling(struct page_pool *pool) if (!pool->p.napi) return; - /* To avoid races with recycling and additional barriers make sure - * pool and NAPI are unlinked when NAPI is disabled. - */ - WARN_ON(!test_bit(NAPI_STATE_SCHED, &pool->p.napi->state)); - WARN_ON(READ_ONCE(pool->p.napi->list_owner) != -1); + napi_assert_will_not_race(pool->p.napi); mutex_lock(&page_pools_lock); WRITE_ONCE(pool->p.napi, NULL); -- 2.39.5